Biological insects are among nature's most nimble fliers, but the kinematic and aerodynamic mechanisms that enable their flight remain an active area of research. Much progress has been made in understanding the biological form and function of flight-capable insects as well as the aerodynamic properties of flapping wing flight, though much remains to be discovered.
Developments in millimeter-scale fabrication processes have led to progress towards creating micro-robotic insects based on their biological counterparts. Insects of the order Diptera have inspired several projects to create similarly scaled micro air vehicles (MAV), including Berkeley's Micromechanical Flying Insect (MFI) [see R. S. Fearing, et al., “Wing transmission for a micromechanical flying insect,” J. Micromechatronics, 1(3), 221-237 (2001)] and the Harvard Microrobotic Fly (HMF) [see R. J. Wood, “The first takeoff of a biologically inspired at-scale robotic insect,” IEEE Trans. Rob., 24, 341-347 (2008)].
Generating aerodynamic forces of a sufficient magnitude is a primary concern for both biological and micro-robotic fliers, Though hovering and executing flight maneuvers also require subtle control over these forces. While a recent demonstration has shown that the HMF design generates sufficient lift to support the mass of its aeromechanical structure, additional mechanisms allowing control over the aerodynamic forces produced by the wings are necessary in order to achieve stable flight.
The addition of kinematic control inputs has been demonstrated to enable active control over the stroke amplitude of each wing of an at-scale microrobotic insect, though not yet on a flight-worthy platform. Evidence exists that biological organisms similarly use flight control muscles to actively apply kinematic perturbations to their wing trajectories, though the complete behavior of these muscles in Dipteran insects is not yet fully understood.
Existing flapping-wing micro air vehicle platforms, including the MFI, the HMF, and others, such as University of Tokyo's butterfly-type ornithopter, the Microbat, Delfly from the Delft University of Technology, and micro air vehicles from the University of Delaware, enforce a kinematic relationship between power-actuation strokes and wing-stroke angles.